sureCore is Developing Cryo-CMOS IP for Quantum Control Chips

One of the challenges to scaling up quantum computers is providing all the necessary control signals to the qubits so that they can implement the needed logic gates for the particular quantum software program. This is especially true for superconducting and spin-qubit based quantum computers that need to run at 4 degrees kelvin or lower. Current implementations start with room temperature signal generation and measurement electronics that sit outside the dilution refrigerator and connect the signals to the qubits using coaxial cables that go through the dilution refrigerator to the qubits at the end. There is great concern that this approach is not scalable for future quantum computers that contain hundreds or thousands of qubits because the mechanical engineering challenges of routing thousands of coaxial wires like this will be too great to overcome.

A number of companies are working on an alternate solution that moves the control electronics inside the dilution refrigerator to run at temperatures of a few degrees kelvin and be positioned very close to the qubits or even integrated on the same chip. This will allow a hardware developer to eliminate the need to route a multitude of cables cables through the dilution refrigerator. One of the issues with developing a cryo-CMOS control chip is that normal CMOS processes are only characterized for operation at operation at -40C to +125C (or 243 - 398 kelvin) and operating the transistors at the lower temperature operate differently. A second problem is that the cooling capability of the dilution refrigerators at these very low temperatures is very limited. So any excess heat thrown off by these cryo-CMOS control chips may overwhelm the cooling capability of the refrigerator causing the temperature to rise and performance degradation of the qubits.

sureCore is a company in Sheffield, UK that specializes in providing very low power CMOS IP and design services for SoC developers requiring these capabilities. They have decided to enter the quantum computing market by developing low power cryo-CMOS IP that runs at a temperature of 4 degrees Kelvin (-269C) for use inside a dilution refrigerator. They will work with foundry partners to characterize the transistors and industry partners to develop control chips that operate at this low temperature. They will leverage their existing ultra low power SRAM technology to develop a version that they call CryoMem.

There are others pursuing this cryo-CMOS approach. In particular, Intel/Qutech unveiled a chip called Horse Ridge II at the ISSCC conference in February and Microsoft published a paper in Nature magazine about their own version of a cryo-CMOS control chip in January. However, neither of these company has disclosed any intention of providing their chips to external customers so the sureCore solution can provide a solution to other companies seeking to take a similar cryo-CMOS approach for their control electronics. For more information, about sureCore's cryo-CMOS activity, you can view a blog post available on their website here.

September 2, 2021